1. Boot menu over serial supported

2. Optimization for booting Solus
3. Optimization for booting .efi file
4. support deepin-live iso
5. support Endless OS
6. framework for booting .img file

GRUB2/MOD_SRC/grub-2.04/include/grub/compiler.h

@@ -0,0 +1,53 @@
+/* compiler.h - macros for various compiler features */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2002,2003,2005,2006,2007,2008,2009,2010,2014  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GRUB_COMPILER_HEADER
+#define GRUB_COMPILER_HEADER	1
+
+/* GCC version checking borrowed from glibc. */
+#if defined(__GNUC__) && defined(__GNUC_MINOR__)
+#  define GNUC_PREREQ(maj,min) \
+	((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
+#else
+#  define GNUC_PREREQ(maj,min) 0
+#endif
+
+/* Does this compiler support compile-time error attributes? */
+#if GNUC_PREREQ(4,3)
+#  define ATTRIBUTE_ERROR(msg) \
+	__attribute__ ((__error__ (msg)))
+#else
+#  define ATTRIBUTE_ERROR(msg) __attribute__ ((noreturn))
+#endif
+
+#if GNUC_PREREQ(4,4)
+#  define GNU_PRINTF gnu_printf
+#else
+#  define GNU_PRINTF printf
+#endif
+
+#if GNUC_PREREQ(3,4)
+#  define WARN_UNUSED_RESULT __attribute__ ((warn_unused_result))
+#else
+#  define WARN_UNUSED_RESULT
+#endif
+
+#define UNUSED __attribute__((__unused__))
+
+#endif /* ! GRUB_COMPILER_HEADER */